Pressure responsive auxiliary disc valve and the like for well cleaning, testing and other operations

ABSTRACT

A full opening pressure operated disc valve particularly suited for cleaning formation perforations by surging and for other operations comprises a rupturable sealing element and a sliding tubular rupture member actuated by a controlled pressure differential between the tubing chamber and the casing annulus, with said element and rupture member being located concentrically within a tubular body and having an ID substantially the same as that of the tubing string.

United States Patent 1191 111.1 3, 31,680

Edwards et a1. 7 Aug. 27, 1974 [54] PRESSURE RESPONSIVE AUXILIARY DISC2,263,412 11/1941 Armentrout 166/297 THE 7 1 2,361,558 10/1944 Mason166/299 2,638,167 5/1953 Jones 166/224 3,589,442 6/1971 Kilgore 166/229OPERATIONS 75 Inventors: Arnold Glen Edwards Charles J. Jenkins, both ofDuncan, Okla. Prlm'y Examner ]ames Leppmk Attorney, Agent, or Firm-John1H. Tregoning [73] Assignee: Halliburton Company, Duncan,

Okla.

[22] Filed: June 28, 1973 [57] ABSTRACT [21] Appl' 374289 A full openingpressure operated disc valve particu- Related US. Application Data larlysuited for cleaning formation perforations by a [62] Division or Ser.No. 224,755, Feb. 9, 1972. Surging and for other Operations Comprises pable sealing element and a sliding tubular rupture 52 US. Cl. 166/311,166/224 member actuated y a controlled pressure differential 51 1111. C1E21b 21/00 between the tubing chamber and the casing annulus, 58 Field61 Search 166 299, 311, 224, 297, with said element and rupture memberbeing located 16 /552 concentrically within a tubular body and having anID substantially the same as that of the tubing string.

[56] References Cited UNITED STATES PATENTS 4 Clam, Drawmg Flgures1,884,165 10/1932 Otis 166/552 g lo s2-\ PATENTEDmszmu .l 3 .I 4 V 4 4(/1.

FIG I sum EN 5 PATENIEUmmum FIG. 2

PAIENIED mszmu PATENIEDMIEZTIQH ass-1380 I WI 5 ll 5 /IOI FIG. 8

i'] v n5 77 I I 78 I #1 FIG. IO i I FIG. 9

PRESSURE RESPONSIVE AUXILIARY DISC VALVE AND THE LIKE FOR WELL CLEANING,TESTING AND OTHER OPERATIONS CROSS REFERENCE TO RELATED APPLICATION Thisis a Division of application Ser. No. 224,755, filed Feb. 9, 1972,entitled PRESSURE RESPON- SIVE AUXILIARY DISC VALVE AND THE LIKE FORWELL CLEANING, TESTING, AND OTHER OPERATIONS."

BACKGROUND OF THE INVENTION Surging is not a new technique, andapparatus for surging a formation can be obtained commercially. Some ofthe types of valves obtainable include those which utilize rupture discssuch as in US. Pat. Nos. 2,565,731; and 2,263,412. Most of the toolsavailable in the prior art contain complex rupturing mechanisms withbulky configurations so that, after the disc is ruptured, flow of fluidfrom the formation through the tool is hindered by the presence of therupturing mechanisms. The devices utilize rupturing techniquesconsisting of dropping heavy metal bars down the tubing to strike therupture mechanism and cause the rupturing of the disc.

Other tools capable of surging and which utilize a surge chamber arethose similar to the one disclosed by US. Pat. No. 3,589,442, which usesan explosive charge to open the surge chamber. These devices occupy agreat amount of the cross-sectional area of the tool and greatlyrestrict flow. They also lack the instantaneous surging effect becausethe actuation mechanism or explosion may initially force fluid anddebris further into the formation before the reaction back into thesurge chamber can occur. Further restrictions in the flow area into thesurge chamber prevent an instantaneous surge.

Tools which utilize fluid pressure to actuate the valve include thosedisclosed in US. Pat. Nos. 3,361,212; 2,855,952; 3,205,955; and 3,211,232. These and other devices generally utilize ball valves or checkvalves in the tubing passage which restrict flow of fluids therethrough.Other types use flow passages running inside the wall of the tool inconjunction with sliding mandrels inside the tool for opening andclosing ports in the interior passages. All of these tools areimpractical for surging due to their restricted flow passages and slowopening nature.

Still other valves in the prior art require lifting and rotating thetubing string one or more times in order to open and close the valveports.

SUMMARY OF THE INVENTION The present invention overcomes these and otherproblems by providing a full-opening instantaneous surging tool which isactuated from thesurface by applying fluid pressure to either the insideof the tubing or the annulus between the tubing and the casing, whichpressure acts on a tubular rupture member forcing it into a rupturablesealing element; breaking the seal in the tubing passage, and allowingfluid in the formation to surge through the fully opened tool into theair-filled surge chamber above the sealing element. carrying sediment,debris, and perforating by-products with it. The tool can then beallowed to set in the well bore until the debris settles out of thefluid into the trap 2 or rathole at the bottom of the well bore, andthen normal testing or production operations can be continued, withthetool ofiering no hindrance to such operations due to its full openingcharacteristic.

The tool is particularly useful as a testing valve when complicatedtesting equipment, commonly termed a christmas tree, is located on thewell at the surface, atop the tubing string, and it is impractical tohave to lift and rotate the tubing string or drop heavy metal bars orballs through the tubing in order to actuate the valve. Use of thisinvention allows pressure to be easily applied through the annulus orthrough the testing apparatus into the tubing to open the valvewhentesting is to begin. After the valve has been used there is no needto withdraw it immediately or drill it out to allow further operationsin the well. Due to its large inner diameter, almost equal to that ofthe tubing string, other tools or devices can be passed down the stringand through the valve without any trouble.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view partly in section ofthe annulus pressure responsive valve, including a. tubular housing, thecutting sleeve, and one rupture disc;

FIG. 2 is a view partly in section of the tubing pressure responsivevalve, including the tubular housing, the cutting sleeve, and onerupture disc;

FIGS. 3 and 4 show the use of single rupture valve as an auxiliary valveor testing valve;

FIGS. 5, 6 and 7 are elevational crosssections of a tubing pressureresponsive disc valve used in conjunc tion with an annulus pressureresponsive disc valve and other standard tools showing the differentstages of surging operations;

FIG. 8 is an axial view of the rupture disc illustrating the scoring inthe disc to allow it to be broken into small parts when rupturing isinitiated;

FIG. 9 represents the method and apparatus for altering surge chamberlength; and

FIG. 10 is a view of an alternative cutting edge for the rupture member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1-10, number1 represents the pressure responsive rupture disc valve in which anupper adapter 2, with internal threads at 20 for securing to the tubingstring, is threadedly connected to the valve seat collar 3 containing avalve seat shoulder 30 upon which is seated the rupturable sealingelement, or rupture disc 4. Valve seat collar 3 contains internalthreads 31 at its upper end and external threads 32 at its lower end.Internal threads 31 mate with external threads 21 of the upper adapter2.

Threadedly attached to valve seat collar 3 are one or more sleevehousings 5. Each sleeve housing has internal threads 51 mating withexternal threads of the adjacent upper member, and has external threads52 at its lower end mating with internal threads on the adjacent lowermember. Each housing 5 has a fluid port 53 communicating from theexterior of the tool to the expansion chamber 6. Interior to andconcentric with the cylindrical sleeve housing 5 is a tubular rupturemember 7 comprising one or more piston sleeves 7A and rupture device 78all of which are hollow tubular cylinders. Abutting the top of thepiston sleeve 7A is a rupture device 78 with an angular cutting edge 71.The

piston sleeves 7A contain shoulders 72 which act as pistons in expansionchamber 6. Expansion chamber 6 and backflow chamber 61 are formedbetween the lower end 33 of the upper adjacent threadedly securedmember, the inner surface of the outer wall 54 of the sleeve housing 5,lower chamber shoulder 55 of the sleeve housing 5, and the piston sleeveitself, which is slidably positioned inside the inner passage of thetool. Circular seals 8 located between the sleeve housing and the pistonsleeve 7A serve to maintain a pressuretight chamber 6.

Threadedly secured to the lowermost sleeve housing 5 is the bottomadapter 9 with internal threads 91 and external threads 92. Externalthreads 92 are for securing the tool to the next tool or next joint ofregular tubing.

Circular seals 10 serve to prevent fluid seepage or pressure loss fromthe interior of the tool to the exterior of the tool or vice versa, andare placed between all components which are threaded together. Circulardisc seal 11 is placed circumferentially around the rupture disc 4 toprevent premature loss of fluid around the rupture disc.

Ports 73 in piston sleeve 7A provide fluid communication between backflow chamber 61 and the interior of the sleeve passage.

In typical operation, referring to FIGS. 3 and 4, the tool 1, asdescribed above, is placed in the tubing string 102 and lowered into thewell bore 103. A packer 114 is usually located beneath the tool 1 on thetubing string 102 and is used to isolate the annulus 104 from the tubingpassage 105. The packer 114 is set when the valve tool 1 has beenlowered to the proper depth in the well. The testing apparatus, orchristmas tree (not shown) can then be attached to the tubing string atthe surface and when it is desirable to begin testing flow, pressure isapplied to the annulus fluid from pumps at the surface, causing apressure differential across the piston shoulder 72 in FIG. 1, causingthe piston sleeve 7A to move upwardly toward the rupture disc 4. Thisforces the cutting sleeve 78 upward toward the disc 4. The cutting edge71 of the cutting sleeve 78 contacts the rupture disc 4 and when theannulus pressure reaches a predetermined level, the cutting sleeve isdriven through the rupture disc 4, fully opening the inner passage ofthe tool 1. The rupture disc may be deeply scored 41 as shown in FIG. 8to facilitate break ing up of the disc while the cutting sleeve 78 ispassing through it, thereby preventing clogging of the passage throughthe cutting sleeve by the severed disc. When the valve is opened, thedisc is almost completely cut out leaving an opening in the disc atleast as large as the outer diameter of the cutting sleeve and allowingpassage of additional tools and devices down through the valve tool 1 toother tools below it. The opening of the valve is thus accomplishedwithout disturbing the testing apparatus at the wellhead. The lack ofinner restrictions allows further work to be done in the well withoutneed of removing the valve 1.

In FIG. 2, a tubing pressure responsive (TPR) valve 101 is revealedwherein all the elements of the annulus pressure responsive (APR) valve1 are present but in slightly different order. The valve seat collar 3and rupture disc 4 have been removed from between the upper adapter 2and the sleeve chamber 5, the disc rotated 180, and both componentsplaced between the sleeve chamber 5 and the bottom adapter 9. The upperadapter 2 and the sleeve chamber 5 are then threadedly secured to eachother. The cutting sleeve 78 is removed from its abutting position atopthe piston sleeve 7A, is rotated 180 so that the cutting edge 71 ispointing downward toward the relocated rupture disc 4, and is insertedin abutting position at the lower end of the piston sleeve 7A. In itsinitial position, the piston sleeve 7A in the TPR valve is pushed to theuppermost point within the valve passage so that shoulder 72 is almosttouching lower lip 56 of the upper adjacent member 2. In operation, theTPR tool 101 is lowered into the well on the tubing string, a packer isset below the tool which isolates the tubing passage from the annulus,and pressure is applied to the tubing passage causing fluid pressure toact through ports 73 and against shoulder 72 attempting to reach thelower pressure area in expansion chamber 6. The resulting pressuredifferential across shoulder 72 forces cutting and piston sleves 7A and7B downward, thereby cutting disc 4 which opens the tool completely.

Referring now to FIGS. 5, 6, and 7, a method for cleaning perforationsin a formation by surging is illustrated using a combination of theannulus pressure respnsive (APR) valve 1 and the tubing pressureresponsive (TPR) valve 101. The APR valve 1 is placed in the drillstring below the TPR valve 101 and is installed such as to leave anair-tight chamber 112 between the two rupture discs 4. As shown in FIG.9, the length of the air chamber 112 can be controlled by the amount oftubing 115 inserted between the APR valve and the TPR valve, if any.

The tools are lowered into the well to the desired depth and circulatingvalves 113 may be used above and below the disc valves 1 and 101.Circulating valves 113 are held open while the tools are being insertedin order to allow fluid in the well to flow through the tubing while itis being lowered into the hole. This facilitates the lowering step andallows the establishment of a fluid cushion 107 above the top disc andextending to the surface. A packer 114 located at the bottom of the wellstring is set and the circulating valves 113 are closed. Commerciallyavailable packers and circulating valves such as those manufactured andsold by Halliburton Company under the designation R'I'lS circulatingvalves and RTTS packers can be used.

Pressure is applied to the annulus 104 which opens the lower disc valve4 exposing the air chamber 112, which is at a comparatively lowpressure, to the comparatively high fluid pressure in the formation 108.The fluid 109 in the formation 108 rushes instantaneously into the airchamber carrying with it debris and perforation by-products, cleaningthe perforations in the formation. The annulus pressure is released andoperations may be ceased for a period of time sufficient to allow thedebris to settle into the trap 110, or rathole, usually five minutes ormore. The tubing passage 105 is then pressured up to the pressurerequired to open the TPR valve 101 which opening then occurs, and thetubing inner passage 105 is then completely clear all the way from theformation 108 to the surface (not shown). If desired, fluid can then bepumped down the annulus and up the tubing carrying out the debris. Flowtests, stimulation treatment, or consolidation applications may beperformed, without interference, through the tubing, and the valves 101and 1 can be I easily removed from the hole if desired.

The tremendous advantages from the use of this invention for surfingoperations derive in part from the full opening characteristics of thetool due to the large ID of the disc cutting means, and from theinstantaneous opening and quick surge obtained. Other tools which areavailable for surging lack the instantaneous surging effect and the fullopening feature of this invention.

It is common knowledge that the velocity of a fluid determines itsability to sweep debris out of the formation. For a given perforationscross-sectional area the flow velocity therethrough is dependent uponthe mass flow rate of the fluid which is permitted into the surge tool.This in turn is a function of the cross-sectional flow area of the toolin its opened position. Due to the large flow area of the tool of thisinvention, maximum flow rates are achieved, giving maximum flow velocityin the perforations and in turn maximum cleaning effect. These maximumsare far above those of the prior art tools due to the restricted flowareas of those tools.

The surging can be controlled by this invention by the use of varyinglengths of surge chamber. A surge chamber is used because it is notdesirable to have surging completely to the surface, for safety reasonsand because such unchecked surge is destructive to the formation.

FIG. 9 illustrates the use of standard tubing 115 between the APR valve1 and the TPR valve NH. The length of the surge chamber 112 can thus'bevaried from a few feet in length with no tubing inserted between the twovalves, to as long as is needed by the insertion of tubing or tubularmembers threaded between the two valves 1 and 10]. Standard tubing isused because of its comparatively low cost and widespread availabilityalthough any strong tubular member of any desired length could serve asan air chamber extension as long as it contained sufficient connectingmeans at its ends to interconnect it between the two valves.

Another advantage of this invention when using in testing withcomplicated apparatus attached to the wellhead is that it is whollyoperable by fluid pressure from the surface and requires no lifting andsetting down nor any rotational motion to activate either type valve.

Other advantages of this invention include the effect of a positiveindication to the operator at the surface as to when the surge begins sothat he can time the settling period accurately. This indicationconsists of a sharp jerk on the tubing string at the opening, whichindication can be amplified by the use of shear means between therupture device and the housing in order to achieve an over-pressuringand a more decisive jerk on the tubing.

Also due to the flow-through design above and below the surge chamberthrough the useof circulating valves above and below the tools, the toolis pressure balanced going into the hole and premature opening isprevented. The tool is safer to use because no manipulation of thetubing is required to open it. It is very simple to operate, dependable,and can be used over and over again merely by replacing the low-costrupture disc.

The pressure required to operate the valve can be varied over anextremely broad range in several ways. One manner of variation is tovary the thickness and/or composition of the rupture disc to vary itsrupture strength. Another method involves varying the differentialpressure area between the piston sleeves and the sleeve housings to varythe activating pressure required. Another method would involve changingthe cutting angle or the sharpness of the cutting edge of the cuttingsleeve. Another method of increasing the available rupturing force is toadd one or more identical piston sleeves 7A and a corresponding numberof sleeve housings 5 to the tool.

Also due to the simplicity of the component parts and theirinterchangeability between TPR usage and APR usage, the tool is veryinexpensive to manufacture when compared to the complex tools of theprior art. The rupture discs can be made of any frangible material suchas magnesium and its alloys, copper and its alloys, aluminum and itsalloys, lnard rubber, plastic, epoxy with glass fibers, phenolics, wood,or glass, as long as the material has sufficient rupture strength toprevent premature opening when going into the well. The discs may beflat or, as in one prepared embodiment herein, they can be domed foradditional strength against ambient pressures which does notsubstantially effect the force required for rupturing. The discs can bescored as in FIG. 8 to obtain several small particles upon rutpuringrather than one large piece.

The remaining components of the tool can be of any tough metal or metalalloy such as steel or stainless steel.

The rupture member 78 is stated as being a tubular sleeve with anangular cutting edge. While this is the preferred embodiment it ispossible that the rupture element might be of non-circular cross sectionand have a squared off cutting edge or a multiangular cutting edge 77with two or more points for rupture as in F 1G. 10. The rupture memberis perferably made of a tough metal such as steel or stainless steel orcan be a drillable material such as aluminum alloy or cast iron.

Seals used may be composed of any commercially available suitablesealing material such as natural or artifical rubber and can be of the Oring type.

Although a specific preferred embodiment of the present invention hasbeen described in the detailed description above, the description is:not intended to limit the invention to the particular forms orembodiments disclosed herein, since they are to be recognized asillustrative rather than restrictive and it will be obvious to thoseskilled in the art that the invention is not so limited. For example,the tool of this invention is described for use as a testing valve orsurging tool but it can also be used as an auxiliary valve. Also, the IDof the valve is stated to be near that of the tubing string but this isnot a necessary limitation as the [D could be reduced to any'desirabledimension by several methods, such as increasing the wall thickness ofthe tubular housing and/or the tubular rupture element. Thus, theinvention is declared to cover all changes and modifications of thespecific example of the invention herein disclosed for purposes ofillustration, which do not constitute departures from the spirit andscope of the invention.

What is claimed is:

l. A well tool for location in a tubing string disposed in a well borefor performing surging operations, wherein annulus fluid is present inthe annulus between the tubing string and the well bore, and tubingfluid is present within the tubing string, and there is further includedmeans for selectively pressurizing the annulus fluid and pressurizingthe tubing fluid, and wherein a first rupture disc carried within thefirst tubular valve body and normally blocking flow through the valvebody and said tubing string; and

means carried by the first tubular valve body responsive topressurization of the annulus fluid for rupturing the first rupture discto allow flow therethrough;

b. a tubing-pressure responsive rupture disc valve,

including: a second tubular valve body; means for connecting the secondtubular valve body to said tubing string in communication therewith;

a second rupture disc carried within the second tubular valve body andnormally blocking flow through the second valve body and saidtubingstring; and v means carried by the second tubular valve body responsiveto pressurization of the tubing fluid for rupturing the second rupturedisc to allow flow therethrough; and

c. a cylindrical tubular air chamber located between saidannulus-pressure responsive valve and said tubing-pressure responsivevalve and joining said valves together, with said valves and air chamberadapted for being interposed in a tubing string.

2. The well tool of claim 1 wherein said air chamber further comprises alength of standard well tubing adaptable at each end for connectingbetween said annulus pressure responsive valve and said tubingpressureresponsive valve.

3. A method of cleaning a well formation by surging debris out of theperforations comprising the steps of:

a. lowering into the fluid in said formation a tool string containing atubing-pressure responsive rupture disc valve, and air chamber attachedthereto, an annulus-pressure responsive disc valve attached to the airchamber and a packer;

b. setting the packer in-the annulus at the lower end of said toolstring;

0. applying fluid pressure to the annulus between said tool string andthe well bore thereby opening said.

tubing to remove said debris after opening said tubing-pressureresponsive valve.

1. A well tool for location in a tubing string disposed in a well borefor performing surging operations, wherein annulus fluid is present inthe annulus between the tubing string and the well bore, and tubingfluid is present within the tubing string, and there is further includedmeans for selectively pressurizing the annulus fluid and pressurizingthe tubing fluid, and wherein packer means is provided for separatingthe annulus fluid from the tubing fluid, comprising: a. anannulus-pressure responsive rupture disc valve, including: a firsttubular valve body; means for connecting the first tubular valve body tosaid tubing string in communication therewith; a first rupture disccarried within the first tubular valve body and normally blocking flowthrough the valve body and said tubing string; and means carried by thefirst tubular valve body responsive to pressurization of the annulusfluid for rupturing the first rupture disc to allow flow therethrough;b. a tubing-pressure responsive rupture disc valve, including: a secondtubular valve body; means for connecting the second tubular valve bodyto said tubing string in communication therewith; a second rupture disccarried within the second tubular valve body and normally blocking flowthrough the second valve body and said tubing string; and means carriedby the second tubular valve body responsive to pressurization of thetubing fluid for rupturing the second rupture disc to allow flowtherethrough; and c. a cylindrical tubular air chamber located betweensaid annulus-pressure responsive valve and said tubing-pressureresponsive valve and joining said valves together, with said valves andair chamber adapted for being interposed in a tubing string.
 2. The welltool of claim 1 wherein said air chamber further comprises a length ofstandard well tubing adaptable at each end for connecting between saidannulus pressure responsive valve and said tubing-pressure responsivevalve.
 3. A method of cleaning a well formation by surging debris out ofthe perforations comprising the steps of: a. lowering into the fluid insaid formation a tool string containing a tubing-pressure responsiverupture disc valve, and air chamber attached thereto, anannulus-pressure responsive disc valve attached to the air chamber and apacker; b. setting the packer in the annulus at the lower end of saidtool string; c. applying fluid pressure to the annulus between said toolstring and the well bore thereby opening said annulus-pressureresponsive valve into said air chamber; d. unsetting said packer; and e.applying fluid pressure to the interior of the tubing of said workstring thereby opening said tubing-pressure responsive rutpure discvalve.
 4. The method of claim 3 further comprising: a. maintaining saidtool string in position, after opening said annulus pressure responsivevalve, for a period of time sufficient to allow debris to settle to thebottom of the well hole, prior to said unsetting step; and b. washingdown said annulus and up through the tubing to remove said debris afteropening said tubing-pressure responsive valve.